N-Arylation of 1,2,4- and 1,3,4-Oxadiazolones under Activated Aromatic Nucleophilic Substitution Conditions

The possibilities of N-arylation of 1,2,4-oxadiazol-5(4H)-ones and 1,3,4-oxadiazol-2(3H)-ones with various electron-deficient chloro- and fluorine-substituted nitroarenes under the conditions of the classical activated nucleophilic substitution reaction were studied. A significant difference was found in the reactivity of 1,2,4- and 1,3,4-oxadiazolones in the N-arylation reactions. Methods for the synthesis of N-nitroaryl derivatives of 1,2,4- and 1,3,4-oxadiazolones, providing the target products of sufficient purity in yields of about 65–96%, were developed.